This project is prompted by the urgent public health need to find optimal nutrition and exercise prevention strategies to reduce future cardiovascular disease and type 2 diabetes risk in young adults. This project aims to investigate the efficacy of a low-glycemic load diet both alone, and in combination with resistance training, to ameliorate endothelial dysfunction, monocyte inflammation and 24-hr glycemic variations. 160 obese young adults will be randomly assigned to 1 of 4 groups for 12 weeks: 1) a control high-glycemic load diet; 2) a low- glycemic load diet; 3) a high-glycemic load diet + resistance training; or 4) low-glycemic load diet + resistance training. The aims are to determine if: 1) a low-GL diet improves endothelial function, monocyte inflammation and 24-hr glycemic variations compared to a standard high-glycemic load, Westernized diet and 2) a low-GL diet + RT has an additive effect with low-GL diet to improve endothelial function, monocyte inflammation and 24-hr glycemic variations. Dependent variables include endothelial function by brachial artery flow-mediated dilation (FMD), monocyte phenotyping by flow cytometry and PCR/protein analysis, 24-hr continuous glucose monitoring systems, insulin sensitivity by frequently sampled intravenous glucose tolerance test, whole body composition by DEXA, visceral and hepatic fat fraction by MRI, and acute responses to a high-glycemic index meal. The hypotheses are that a low-glycemic load diet will improve the above key cardiovascular risk related dependent variables and that the addition of resistance training will induce additive effects. This project will, for the first time, compare the isolated and combined effects of a low-glycemic load diet and/or resistance training on endothelial function, monocyte inflammation and 24-hr glycemic variations. If the hypotheses are upheld, new therapeutic options will become available to improve primary prevention of vascular dysfunction, chronic inflammation and insulin resistance, including in those young adults where alternative therapies may be less effective. PUBLIC HEALTH RELEVANCE: For the first time, a randomized controlled trial using a low glycemic-load diet and/or resistance training will be carried out in obese young men and women. This efficacy trial should have major public health implications to the tens of millions of Americans currently obese, presenting with less than optimal vascular function, chronic inflammatory status and insulin sensitivity, thus providing insight into novel preventive health strategies. Furthermore, due to individualized specificity of compliance issues for each patient, the arsenal of therapies for prescription needs to be large; the current proposal will potentially increase the range of therapies.